Fighting the U-boats

The US Silent Service in Early WWII: A Story of Failure

Shortly after noon on December 8, 1941, waves of Japanese twin-engine bombers and Zero assault fighters struck the US Far East Air Force based primarily at Clark Field near Manila, Philippines. Despite advance warning from Pearl Harbor, all aircraft were caught on the ground and swiftly shot to pieces-the Hawaii debacle, which had taken place 8 hours earlier, repeated itself with painful similarity. Within two hours, the entire Asiatic air squadron, including the vaunted B-17 bombers, was wiped out.

With the destruction of the US Air Force, Far East, the only weapon left to hurl against the onrushing Japanese invasion fleets was the 29 submarines of the Asiatic Fleet. To protect the surface ships from air raid, the Fleet commander, Admiral Hart, had dispatched them to the Dutch East Indies (where they would soon fall victim to the Nihon Kaigun, the Japanese Navy). The submarines were the last hope for deflecting the seaborne invasion force that would soon close in on the Philippines. In fact, however, the US subs achieved little more than minor disturbances.
The reasons were numerous. First, although the Asiatic Fleet had roughly the number of operational boats Admiral Dönitz had as of 3 September, 1939, the training of its crews and skippers was nowhere near that of the their German colleagues. The US skippers were overly cautious in their attack runs, and some of them even experienced nervous breakdowns as their boats came under depth charge attacks (Miller 214).

Second and more important, the performance of the subs' torpedoes was disastrous. A couple of examples suffice to illustrate the sorry state of the Asiatic Silent Service at that time. The USS Sargo, for example, lobbed a total of 13 fish at enemy convoys without scoring a single hit (Ibid.). Even more frustrating was the experience of the Tinosa. The boat encountered a 20,000-ton tanker shortly after the outbreak of hostilities, and fired a total of 15 torpedoes at the big Maru…of which only 2 detonated. The rest simply slammed against the hull and bounced off. Even the two fish that did explode failed to sink the ship, but merely damaged her. In all, the situation around the Philippines at the time was best epitomized by the New York Times: "We had the greatest concentration of submarines in the world there," rang the tabloid, "but we didn't do a thing!" (Miller 483)

Considered within a broader framework, the failure of the US subs to contest the Japanese invasion of the Philippines confirmed once again an important conclusion on submarine warfare, first enunciated by Admiral Karl Dönitz in the wake of Operation Weser?bung (the invasion of Norway) in 1940. Submarines perform at their best when used in offensive, not defensive operations. Rather than react to enemy movements-often too late-submarines should set their own tempo and time of attack.

It would be proper to mention at this point that the earlier failures of US submarines probably prejudiced the Nihon Kaigun (the Japanese Navy) against the importance of anti-submarine warfare. Furthermore, convoys and other measures were considered defensive in nature (which of course they were), and thus unbecoming the samurai spirit. Even later into the war, when the US subs started to make a difference, the Nihon Kaigun continued to neglect convoys and ASDIC and let merchantmen sail on their own. It was a mistake that would cost Japan the war.
But during late 1941 and 1942, US subs accumulated such an impressive list of failures, that earlier critiques resurfaced, questioning the usefulness of the submarine per se in naval warfare. An analysis of the period reveals that the problems plaguing the Silent Service were largely the same as those the German U-Bootwaffe had faced-and resolved-two years earlier. The two main components of the US submarine arsenal were the Mark XIV-steam-driven-and the Mark VI torpedoes. The Mark XIV relied on magnetic pistols to detonate the warhead, and the Mark VI was armed with impact detonators. The former exhibited two kinds of failures: premature detonation and vertical deviation from the course set, while the latter simply jammed on impact.

Writes Captain Edward Beach, the submariner-historian: "The torpedo situation during the first half of the war was a national disgrace and the negligent perpetrators responsible should have been severely punished" (484). Admiral Dönitz would have readily agreed. He himself saw to it that the bureaucrats responsible for the early failures of the U-Bootwaffe were court-martialled. However, nothing similar ever happened to the US Bureau of Ordnance.

As more and more failure reports poured into the new submarine HQ at Fremantle, Australia, Flag Officer Submarines Rear Admiral Charles Lockwood was led to think that more was at fault with the Silent Service than the poor training of the crews. As a matter of fact, US submariners gradually learned their trade as the Pacific War progressed. Unlike their German colleagues in the Verdammter Atlantik, the Americans faced feeble anti-submarine measures and thus had the chance to learn by trial and error. In the raucous mayhem of Atlantic convoy battles, error often meant quick, frigid death.

Analyzing the weaknesses of the Silent Service, Admiral Lockwood eventually pinpointed torpedoes as a possible culprit. Accordingly, he pressed the Bureau of Ordnance (BO), the Navy's supplier, for torpedo tests. The Bureau, however, repeatedly brushed his requests aside with infallible confidence in its torpedoes, and instead insisted that the submariners operating the weapons were incompetent.

Exasperated by such bureaucracy, Lockwood ran extensive tests of his own. The results were appalling. The Admiral lost no time in documenting them and appealing directly to Admiral King, C-in-C of the US Navy. A one-time submariner, King made the lives of the BO hell. The Bureau was finally forced to conduct torpedo tests, which confirmed Lockwood's results. The cumbersome machinery to improve torpedo performance was finally set into motion.

The problem with the premature detonation of the Mark XIV proved the subtlest of all. A magnetic detonator is usually set to explode beneath the ship, with the trigger being the ship's magnetic filed. The shape of the magnetic field, however, depends on the ship's position on the surface of the Earth. Therefore, the shape of the field at Newport, Rhode Island, where the magnetic detonators were originally developed, was quite different from that in the Southwest Pacific. The failure to note this subtle, yet crucial difference explains many of the disappointments that submarine skippers experienced in the first half of the war. The depth-control device of the Mark XIV was also found to be defective, which explained why the fish often plunged towards the bottom instead of steering straight at the target.
As for the Mark VI, the impact detonator was replaced with an improved one. The failure to note the defect earlier was due to the BO's reluctance to test the torpedoes in peacetime. Fish cost $10,000 apiece, and it was considered prodigious to expend them on target practice. In comparison, a similar German torpedo cost RM 25,000-but the Germans never shied away from such "peacetime expenditures."

Even with the improvements made, the Silent Service's troubles were far from solved. Skippers continued to report premature detonations and significant horizontal deviations in the torpedo run. Failure reports, however, did decrease after 1943, and the US Navy kept working on continuous torpedo improvement and upgrade.

The problems with training and experience were also dealt with. As already mentioned, US submariners gradually started to learn their trade, and skippers who were too cautious or timid were replaced without much explanation with younger, eager and aggressive volunteers. The Navy recruited for the Silent Service with great flamboyance, much like the Germans recruited for the U-Bootwaffe, and slowly but surely a new generation of hungry, unforgiving sea wolves came into being, raking Japan's supply lines with increasing success.

Submarine production also increased. Shipyards in California churned out boats for the Pacific much faster than the Japanese could sink them. A total of 288 boats operated in the Pacific during 1941-1945, accounting for a total of 4,861,000 GRT of merchant shipping (warship losses excluded). Thus, "a force containing less than 2 percent of the US Navy's personnel accounted for 55 percent" of Japanese naval losses (Miller 490).

The US Silent Service was also quite successful against Japanese warships, most notably during the last two years of the war. In all, US subs sank 276 warships, including 1 battleship, 8 fleet carriers and 11 cruisers. In comparison, German U-boats sank 2 battleships, 3 fleet carriers, and 2 escort carriers-all of them British. The only major US loss was the escort carrier USS Block Island, torpedoed off Casablanca in 1944 along with a few of her escort ships.
Again for the purposes of comparison, it is necessary to note that German shipyards exceeded US submarine productivity several times, launching over 1,100 U-boats for the duration of the war. The achievements of Die U-boot Krieg, however, were not proportionately greater than US successes, because the U-boats had a much tougher job in the Atlantic, having to deal with a constantly improving convoy system, continuous air patrol and Allied technological innovations. Due to all of the above, German submarine losses-especially after 1942-by far exceeded American losses.

A comparison of the tonnage sunk also tells a good story. The U-boats alone sank over 12 million GRT of Allied merchant shipping as opposed to the nearly 9 million tons of Japanese shipping accounted for by the US Armed Forces as a whole. The essential difference between the Allies and the Japanese, however, was that the Allies could replace and exceed the tonnage lost, while the Japanese could do so only until 1943. More important, "taking a leaf out of Admiral Dönitz's book," US Naval Command placed increased importance-especially in 1944 and 1945-on the type of tonnage being sunk, quality rather than quantity. The Silent Service was ordered to concentrate on oil tankers, and US subs did so with such success that they effectively brought about the collapse of the Japanese war machine. However, according to US military assessments at the time, that was not equivalent to the collapse of the Japanese war effort-and from this conclusion, the decision to unleash a nuclear holocaust on Japanese civilians was only a step away.